<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <!-- select 关联的是 option的value值
      select 的value是可读可写的
      读  document.querySelector('select').value
      写  document.querySelector('select').value = '1'
  -->
  <select>
    <option value="1">北京</option>
    <option value="2">上海</option>
    <option value="3">广州</option>
    <option value="4">深圳</option>
    <option value="5">杭州</option>
    <option value="6">成都</option>
    <option value="7">重庆</option>
  </select>
</body>
</html>